Live › vulnerability › CVE-2026-99125
Go to dashboardThe s390 PAI performance monitoring driver in the Linux kernel could receive two back-to-back PMU stop callbacks when sampling was throttled and a task was then removed from the CPU. The sources do not describe an attacker outcome beyond a kernel driver state fix.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-28 11:32 UTC. All times on this page are UTC.
Systems running the Linux kernel on IBM Z (s390) hardware with the PAI perf PMU driver in use. Other architectures and kernels without this driver are not affected.
No product ranges from the sources yet.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
s390/pai: Handle multiple PMU stop callback invocations
Handle the following scenario: The kernel protects itself against a very high sampling load and throttles the sampling using:
perf_event_throttle() --> PMU->stop()
Shortly later the scheduler may terminate the task and removes it from the CPU. It again calls
PMU->stop()
which results in two invocations of PMU->stop() called back to back. Protect against this and check the PERF_HES_STOPPED bit on function entry. If it is already set return. Clear bit PERF_HES_STOPPED in PMU->start().
Prohibit ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call for this event. It sets perf_event::event_limit to a positive value and causes perf_event_overflow() to invoke pai_stop() call back function when perf_event::event_limit hits zero. This is not supported because the sample events CRYPTO_ALL and NNPA_ALL are only taken at schedule out of a task.
Use list_for_each_entry_safe() for safe iteration over syswide_list in pai_have_samples().
This page as .md · .json · in your agent: get_signal("CVE-2026-99125")
NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.